Cover plate assembly and battery cell

Abstract

The invention relates to a cover plate assembly and a battery cell, and relates to the technical field of batteries, the cover plate assembly comprises a cover plate and an explosion-proof valve, and the cover plate is provided with a liquid injection hole; the anti-explosion valve is arranged in the liquid injection hole and comprises a blasting part and a mounting part, the mounting part is arranged around the blasting part, the inner wall of the mounting part is connected with the blasting part, the outer wall of the mounting part is connected with the inner wall of the liquid injection hole, and the mounting part is provided with a buffer groove. According to the cover plate assembly and the battery cell, part of procedures can be omitted, the production efficiency is improved, the problem that welding marks are prone to cracking can be solved, and the welding quality is improved.

Description

Technical Field

[0001] This application relates to the field of battery technology, specifically to a cover plate assembly and a battery cell. Background Technology

[0002] Currently, the cover plate in a battery cell has an injection hole and an explosion-proof hole. The injection hole is used to inject electrolyte into the cell. After the electrolyte is injected, a seal is installed into the injection hole to seal it. The explosion-proof hole is used to install an explosion-proof valve. When the internal pressure of the cell is too high, the explosion-proof valve opens to release the gas inside the cell. In related technologies, the injection hole and the explosion-proof hole are two different holes, requiring different processing steps to form. The seal and the explosion-proof valve also need to be installed in different steps, resulting in low production efficiency. Furthermore, during the welding of the explosion-proof valve into the explosion-proof hole, the weld between the explosion-proof valve and the explosion-proof hole is prone to cracking, affecting the welding quality. Summary of the Invention

[0003] To address the aforementioned technical problems, embodiments of this application provide a cover plate assembly and a battery cell, which can omit some processes, improve production efficiency, and alleviate the problem of easy cracking of solder joints, thereby enhancing welding quality.

[0004] In a first aspect, a cover plate assembly is provided, comprising: The cover plate is equipped with an injection hole; An explosion-proof valve is disposed in the injection hole. The explosion-proof valve includes a bursting part and a mounting part. The mounting part is arranged around the bursting part. The inner wall of the mounting part is connected to the bursting part. The outer wall of the mounting part is connected to the inner wall of the injection hole. The mounting part is provided with a buffer groove.

[0005] According to a first aspect of this application, the buffer groove has a ring-shaped structure and is arranged around the blasting part.

[0006] According to a first aspect of this application, the blasting part is provided with a groove, the opening of which faces opposite to the opening of the buffer groove.

[0007] According to a first aspect of this application, the bottom wall of the groove is provided with a scoring groove.

[0008] According to a first aspect of this application, the groove includes a first groove segment and a second groove segment distributed circumferentially along the blasting portion, wherein the depth of the first groove segment is greater than the depth of the second groove segment.

[0009] According to a first aspect of this application, the first slot segment and the second slot segment are connected end to end.

[0010] According to a first aspect of this application, the depth of the groove is A, the thickness of the explosion-proof valve is H, and A and H satisfy: 0.3mm≤A≤0.8H.

[0011] According to a first aspect of this application, the mounting portion includes: First sidewall; The second sidewall is disposed opposite to the first sidewall along the thickness direction of the explosion-proof valve; A connecting wall is disposed between the first sidewall and the second sidewall. The connecting wall includes a guide section and a straight section. The guide section is connected to the first sidewall, and the straight section connects the guide section and the second sidewall. The guide section extends obliquely from the first sidewall in a direction away from the axis of the explosion-proof valve, relative to the axis of the explosion-proof valve. The straight section and the axis of the explosion-proof valve are both arranged parallel to the thickness direction of the explosion-proof valve.

[0012] According to a first aspect of this application, the length of the straight segment along the thickness direction of the explosion-proof valve is B, and B satisfies: 0.05mm≤B≤0.2mm.

[0013] Secondly, a battery cell is also provided, including: The casing has an opening; The pole assembly is located within the housing; As described in the previous embodiment, the cover plate assembly is located at one end of the electrode assembly, and the cover plate is connected to the housing to close the opening.

[0014] The cover plate assembly and battery cell provided in this application embodiment, firstly, combine the liquid injection hole and the explosion-proof hole into one, so that the liquid injection hole can both assist in the liquid injection function and be used to assemble the explosion-proof valve. In this way, the number of holes processed on the cover plate can be reduced during the manufacturing process, eliminating processing steps and improving production efficiency. Secondly, by assembling the explosion-proof valve in the liquid injection hole, the explosion-proof valve can seal the liquid injection hole to prevent electrolyte leakage when it is not open; when the explosion-proof valve is open, it can assist in the discharge of gas inside the battery cell to prevent the problem of explosion caused by excessive gas pressure. That is, the explosion-proof valve can achieve both explosion-proof function and explosion-proof function. Furthermore, it can achieve a sealing function, thus eliminating the need for processing and assembling sealing components in actual manufacturing, effectively improving production efficiency. Thirdly, by setting a buffer groove on the mounting part, the buffer groove allows the mounting part to release deformation, thereby releasing residual welding stress. This effectively reduces the risk of stress concentration in the weld, improves the problem of easy cracking of the weld, and effectively improves the welding quality. In addition, the buffer groove can also increase the overall heat dissipation area of ​​the explosion-proof valve, enabling the explosion-proof valve to achieve more efficient heat dissipation during welding, and avoiding the problem of cracking due to overheating during welding. Attached Figure Description

[0015] The above and other objects, features, and advantages of this application will become more apparent from the more detailed description of the embodiments of this application in conjunction with the accompanying drawings. The drawings are provided to further illustrate the embodiments of this application and form part of the specification. They are used together with the embodiments of this application to explain this application and do not constitute a limitation thereof. In the drawings, the same reference numerals generally represent the same components or steps.

[0016] Figure 1 This is a schematic diagram of the structure of a cover plate assembly provided for an exemplary embodiment of this application.

[0017] Figure 2 A partial cross-sectional view of a cover plate assembly provided for an exemplary embodiment of this application.

[0018] Figure 3 A schematic diagram of the structure of an explosion-proof valve provided as an exemplary embodiment of this application from a first-view perspective.

[0019] Figure 4 A schematic diagram of the explosion-proof valve provided in an exemplary embodiment of this application from a second perspective.

[0020] Figure 5 This is a schematic diagram of the explosion-proof valve provided in an exemplary embodiment of this application from a third-person perspective.

[0021] Figure 6 A cross-sectional view of an explosion-proof valve provided for an exemplary embodiment of this application.

[0022] Reference numerals: 100-Cover plate assembly; 110-Cover plate; 111-Injection hole; 120-Explosion-proof valve; 121-Explosion section; 122-Mounting section; 1221-First side wall; 1222-Second side wall; 1223-Connecting wall; 12231-Guide section; 12232-Straight section; 123-Buffer groove; 124-Groove; 125-Scratched groove; 1251-First groove section; 1252-Second groove section; 126-Connecting block. Detailed Implementation

[0023] Hereinafter, exemplary embodiments according to this application will be described in detail with reference to the accompanying drawings. Obviously, the described embodiments are merely some embodiments of this application, and not all embodiments of this application. It should be understood that this application is not limited to the exemplary embodiments described herein.

[0024] The battery cell provided in this application embodiment may include a housing and an electrode assembly. The housing has an opening through which the electrode assembly can extend into the housing. The housing protects the electrode assembly and prevents external objects from damaging it.

[0025] Figure 1 This is a schematic diagram of the structure of a cover plate assembly provided for an exemplary embodiment of this application. Figure 1 As shown, the battery cell may also include a cover assembly 100, which may include a cover 110. The cover 110 is typically located at one end of the electrode assembly and is connected to the housing. The cover 110 can be used to close the opening of the housing. It should be understood that the cover 110 can also protect the electrode assembly and prevent external foreign objects from entering the electrode assembly.

[0026] like Figure 1 As shown, the cover plate 110 is provided with an injection hole 111. In practical applications, electrolyte can be injected into the housing through the injection hole 111, and the electrolyte wets the electrode assembly.

[0027] Figure 2 A partial cross-sectional view of a cover plate assembly provided for an exemplary embodiment of this application. Figure 1 and Figure 2 As shown, the cover plate assembly 100 may also include an explosion-proof valve 120, which is disposed in the injection hole 111.

[0028] It should be noted that in this embodiment, the injection hole 111 and the explosion-proof hole are combined into one. The injection hole 111 can both perform auxiliary injection function and be used to assemble the explosion-proof valve 120. In this way, the number of holes on the cover plate 110 can be reduced during the processing, eliminating processing steps and improving production efficiency.

[0029] It should be noted that, on the one hand, when an abnormal situation occurs in the electrode assembly (such as overcharging, over-discharging, short circuit, etc.) causing the internal gas pressure to reach the pressure threshold, the explosion-proof valve 120 can open to quickly release gas, reduce the internal gas pressure of the battery cell, and prevent safety accidents such as combustion and explosion caused by excessive gas pressure. On the other hand, when the explosion-proof valve 120 is not open, it can seal the electrolyte injection hole 111 to prevent electrolyte leakage. That is, under this operating condition, the explosion-proof valve 120 can function as a sealing element in related technologies. Therefore, the explosion-proof valve 120 can achieve both explosion-proof and sealing functions. In actual processing, the processes of machining and assembling sealing elements can be omitted, effectively improving production efficiency.

[0030] Figure 3 A schematic diagram of the structure of an explosion-proof valve provided as an exemplary embodiment of this application from a first-view perspective. Figure 4 A schematic diagram of the explosion-proof valve provided in an exemplary embodiment of this application from a second perspective. Figure 5 This is a schematic diagram of the explosion-proof valve provided in an exemplary embodiment of this application from a third-person perspective. Figure 6 A cross-sectional view of an explosion-proof valve provided for an exemplary embodiment of this application. (See attached image.) Figures 2 to 6As shown, the explosion-proof valve 120 may include a bursting part 121 and a mounting part 122. The mounting part 122 is arranged around the bursting part 121, and the inner wall of the mounting part 122 is connected to the bursting part 121. It can be understood that after the explosion-proof valve 120 is installed into the injection hole 111, the outer wall of the mounting part 122 is connected to the inner wall of the injection hole 111.

[0031] It should be noted that when the gas inside the battery cell reaches the pressure threshold, the burst section 121 ruptures under the action of gas pressure, and the gas can be discharged from the rupture point of the burst section 121, thereby reducing the gas pressure inside the battery cell.

[0032] In one embodiment, the mounting part 122 and the blasting part 121 are integrally formed, which makes the processing more convenient and can also ensure the overall structural strength of the explosion-proof valve 120.

[0033] In one embodiment, the mounting part 122 and the blasting part 121 can also be connected by welding, bonding or other means.

[0034] It should be noted that welding the outer wall of the mounting part 122 to the inner wall of the injection hole 111 can fix the explosion-proof valve 120 inside the injection hole 111, preventing the explosion-proof valve 120 from detaching from the injection hole 111 and improving the assembly stability of the explosion-proof valve 120 within the injection hole 111. Furthermore, the weld mark formed by welding the outer wall of the mounting part 122 to the inner wall of the injection hole 111 can seal the gap between the outer wall of the mounting part 122 and the inner wall of the injection hole 111, effectively improving the sealing performance of the explosion-proof valve 120 and preventing electrolyte leakage from the gap between the outer wall of the mounting part 122 and the inner wall of the injection hole 111.

[0035] It should be noted that during the welding process between the outer wall of the mounting part 122 and the inner wall of the injection hole 111, residual welding stress will be generated. This residual stress has nowhere to be released, which can easily lead to weld cracking, affecting the welding quality and causing the explosion-proof valve 120 to loosen within the injection hole 111. Therefore, as... Figures 4 to 6 As shown in the embodiment of this application, the mounting part 122 is provided with a buffer groove 123, which can solve the aforementioned problems.

[0036] Specifically, during the welding process between the outer wall of the mounting part 122 and the inner wall of the injection hole 111, residual welding stress acts on the mounting part 122, causing deformation. The buffer groove 123 allows the mounting part 122 to release this deformation, thereby releasing residual welding stress. In other words, the buffer groove 123 effectively reduces the risk of stress concentration in the weld, improves the problem of weld cracking during the welding process between the outer wall of the mounting part 122 and the inner wall of the injection hole 111, and effectively improves welding quality.

[0037] It should be noted that, compared with the related technologies that do not have a buffer groove 123, in this embodiment, the buffer groove 123 is provided in the mounting part 122, which can increase the overall heat dissipation area of ​​the explosion-proof valve 120. In this way, the explosion-proof valve 120 can achieve more efficient heat dissipation during the welding process, and avoid the explosion-proof valve 120 from cracking due to overheating during the welding process.

[0038] The cover plate assembly 100 and battery cell provided in this application embodiment, in a first aspect, combine the liquid injection hole 111 and the explosion-proof hole into one, so that the liquid injection hole 111 can both perform auxiliary liquid injection and be used to assemble the explosion-proof valve 120. In this way, the number of holes processed on the cover plate 110 can be reduced during the processing, eliminating processing steps and improving production efficiency. In a second aspect, by assembling the explosion-proof valve 120 in the liquid injection hole 111, the explosion-proof valve 120 can seal the liquid injection hole 111 when it is not open, preventing electrolyte leakage; when the explosion-proof valve 120 is open, it can assist in the discharge of gas inside the battery cell, preventing the problem of explosion caused by excessive gas pressure. That is, the explosion-proof valve 120 can both perform auxiliary liquid injection and be used to assemble the explosion-proof valve 120. It achieves both explosion-proof and sealing functions. Therefore, in actual processing, the processes of machining and assembling the sealing components can be omitted, effectively improving production efficiency. Thirdly, by setting a buffer groove 123 on the mounting part 122, the buffer groove 123 allows the mounting part 122 to release deformation, thereby releasing residual welding stress. This effectively reduces the risk of stress concentration in the weld, improves the problem of easy cracking of the weld, and effectively improves the welding quality. In addition, the buffer groove 123 can also increase the overall heat dissipation area of ​​the explosion-proof valve 120, enabling the explosion-proof valve 120 to achieve more efficient heat dissipation during welding, and avoiding the problem of cracking of the explosion-proof valve 120 due to overheating during welding.

[0039] like Figure 3 As shown, the buffer groove 123 is arranged around the blasting part 121. That is, the buffer groove 123 has a ring-shaped structure. In this way, along the circumference of the blasting part 121, the buffer groove 123 can provide the installation part 122 with deformation release in different directions. In other words, the buffer groove 123 can release welding residual stress in multiple directions, which can reduce the risk of stress concentration in the weld in different directions and improve the problem of easy cracking of the weld in different directions.

[0040] In one embodiment, there can be multiple buffer grooves 123. The multiple buffer grooves 123 are distributed radially along the explosion-proof valve 120. The multiple buffer grooves 123 can be used to gradually accommodate the deformation of the mounting part 122. During the welding process between the outer wall of the mounting part 122 and the inner wall of the injection hole 111, the multiple buffer grooves 123 can play the role of releasing welding residual stress step by step, and further eliminate welding residual stress.

[0041] like Figure 2 and Figure 6 As shown, the rupture section 121 has a groove 124. This allows the thickness of the rupture section 121 to be less than the thickness of the mounting section 122. When the internal gas pressure of the battery cell reaches the pressure threshold, the rupture section 121 can rupture before the mounting section 122, allowing gas to escape from the rupture point and reducing the internal gas pressure of the battery cell. Even if the rupture section 121 ruptures, the mounting section 122 can remain tightly connected to the inner wall of the injection hole 111, preventing the explosion-proof valve 120 from being blown out by the gas pressure and avoiding damage to other components and personnel.

[0042] like Figure 2 and Figure 6 As shown, the opening of the groove 124 faces the opposite direction to the opening of the buffer groove 123. Specifically, in practical applications, when the explosion-proof valve 120 is installed into the injection hole 111, the opening of the groove 124 faces the electrode group, and the opening of the buffer groove 123 faces the outer area of ​​the cover plate 110 (that is, the area of ​​the cover plate 110 away from the electrode group).

[0043] It should be noted that the buffer groove 123 is arranged around the groove 124. The buffer groove 123 and the groove 124 are arranged in different positions. The opening of the groove 124 faces the opposite direction to the opening of the buffer groove 123. This can make full use of the physical structure of the explosion-proof valve 120 at different parts to ensure the structural strength between the mounting part 122 and the blasting part 121.

[0044] Furthermore, when welding the outer wall of the mounting portion 122 to the inner wall of the injection hole 111, the weld mark is formed on the side of the cover plate 110 away from the electrode assembly. This makes the side of the mounting portion 122 away from the electrode assembly more prone to deformation. Therefore, having the opening of the buffer groove 123 facing the outer region of the cover plate 110 (i.e., the region of the cover plate 110 away from the electrode assembly) is more conducive to releasing the deformation of the mounting portion 122 into the buffer groove 123, and thus more conducive to releasing residual welding stress.

[0045] Furthermore, a lower plastic layer is provided on the inner side of the cover plate 110 (i.e., the area of ​​the cover plate 110 near the electrode assembly). This lower plastic layer is used to prevent the cover plate 110 from directly contacting the electrode assembly. Therefore, by facing the opening of the groove 124 toward the electrode assembly, the lower plastic layer on the inner side of the cover plate 110 can be prevented from directly contacting the explosion-proof valve 120, thereby preventing the lower plastic layer from damaging the explosion-proof valve 120.

[0046] like Figure 2 as well as Figures 4 to 6As shown, the bottom wall of the groove 124 is provided with a scoring groove 125. It should be noted that the scoring groove 125 can further reduce the thickness of the bottom wall of the groove 124. When the gas pressure inside the battery cell reaches the pressure threshold, the part of the bursting section 121 corresponding to the scoring groove 125 is more likely to break, that is, the gas can be discharged more promptly, avoiding excessive gas pressure accumulation inside the battery cell.

[0047] It should be noted that the scoring groove 125 is set on the bottom wall of the groove 124, and the opening of the scoring groove 125 faces the electrode group. In this way, on the one hand, the air pressure inside the cell can directly act on the weak area of ​​the scoring groove 125, ensuring that the corresponding part of the scoring groove 125 will break in time and accurately when the air pressure reaches the pressure threshold; on the other hand, compared with the scheme where the opening of the scoring groove 125 faces the outside of the cover plate 110 (the side of the cover plate 110 away from the electrode group), the opening of the scoring groove 125 facing the electrode group can avoid the accumulation of foreign objects in the external environment inside the scoring groove 125, reduce the risk of abnormal breakage, and improve the overall reliability of the explosion-proof valve 120.

[0048] In one embodiment, the groove 125 can be annular. This way, when the internal gas pressure of the battery cell reaches a pressure threshold, the bursting part 121 corresponding to the groove 125 can rupture at different locations, effectively improving gas emission efficiency.

[0049] like Figures 4 to 6 As shown, the groove 125 may include a first groove segment 1251 and a second groove segment 1252 distributed circumferentially along the burst portion 121, with the depth of the first groove segment 1251 being greater than the depth of the second groove segment 1252. Therefore, the thickness of the portion of the burst portion 121 corresponding to the first groove segment 1251 is less than the solid thickness of the portion of the burst portion 121 corresponding to the second groove segment 1252. When the gas pressure inside the battery cell reaches the pressure threshold, the portion of the burst portion 121 corresponding to the first groove segment 1251 ruptures, and the ruptured portion can be used to release gas. However, the portion of the burst portion 121 corresponding to the second groove segment 1252 will not rupture at this time. This prevents the burst portion 121 from completely detaching from the mounting portion 122, thereby avoiding the burst portion 121 flying out and damaging other components.

[0050] Combination Figure 4 and Figure 5 By incorporating a connecting block 126 within the groove 125, a first groove segment 1251 and a second groove segment 1252 of different depths can be formed. For example, as... Figure 4 and Figure 5 As shown, a connecting block 126 is provided at one location within the groove 125. The groove segment corresponding to the connecting block 126 forms the second groove segment 1252, and the groove segments at other locations form the first groove segment 1251.

[0051] like Figure 4 and Figure 5 As shown, the first groove segment 1251 and the second groove segment 1252 are connected end to end. This facilitates the simultaneous formation of the first groove segment 1251 and the second groove segment 1252 in the same processing step, thereby improving the processing efficiency of the first groove segment 1251 and the second groove segment 1252.

[0052] For example, in one embodiment, an arc-shaped column can be provided in the mold, wherein the height of the first part of the arc-shaped column is higher than the height of the second part. In the actual production process, the first part of the arc-shaped column can form a first groove segment 1251 corresponding to the forming part, and the second part of the arc-shaped column can form a second groove segment 1252 corresponding to the forming part.

[0053] like Figure 6 As shown, the depth of the groove 124 is A. If the depth A of the groove 124 is too small, the explosion-proof valve 120 may get too close to the lower plastic inside the cover plate 110, which may damage the explosion-proof valve 120. If the depth A of the groove 124 is too large, the overall strength of the explosion-proof valve 120 may decrease, which may lead to the explosion-proof valve 120 being triggered falsely, affecting the stability of the battery cell.

[0054] Therefore, in this embodiment of the application, the depth A of the groove 124 is limited to the following range: 0.3mm≤A≤0.8H, where H can be understood as the thickness of the explosion-proof valve 120. In this way, the problems caused by the groove 124 being too large or too small can be effectively improved.

[0055] In one embodiment, the depth A of the groove 124 can be selected as 0.3mm, 0.5H, 0.8H, etc.

[0056] It should be noted that the thickness H of the explosion-proof valve 120 can be set according to the actual situation, and this application embodiment does not make a specific limitation on this.

[0057] like Figure 6 As shown, the mounting portion 122 may include a first sidewall 1221, a second sidewall 1222, and a connecting wall 1223. The first sidewall 1221 and the second sidewall 1222 are along the thickness direction of the explosion-proof valve 120 (see reference). Figure 6 The connecting wall 1223 is disposed between the first sidewall 1221 and the second sidewall 1222 (in the Z-axis direction). The connecting wall 1223 can connect the first sidewall 1221 and the second sidewall 1222. Specifically, the connecting wall 1223 may include a guide segment 12231 and a straight segment 12232. The guide segment 12231 is connected to the first sidewall 1221, and the straight segment 12232 connects the guide segment 12231 and the second sidewall 1222.

[0058] It should be noted that the guide section 12231 extends from the first sidewall 1221 toward the axis away from the explosion-proof valve 120 (reference). Figure 6 The guide section 12231 extends at an angle relative to the axis of the explosion-proof valve 120 in the direction of the straight line indicated by the middle arrow M. During the process of installing the explosion-proof valve 120 into the injection hole 111, the guide section 12231 can guide the explosion-proof valve 120 to be quickly assembled into the injection hole 111, which can improve the assembly efficiency of the explosion-proof valve 120.

[0059] In one embodiment, the guide section 12231 is aligned with the axis of the explosion-proof valve 120 (reference). Figure 6 The angle between the lines indicated by the middle arrow M can be 30°, 60°, etc.

[0060] It should be noted that the aforementioned straight segment 12232 and the axis of the explosion-proof valve 120 (refer to...) Figure 6 The straight line indicated by the middle arrow M is aligned with the thickness direction of the explosion-proof valve 120 (reference). Figure 6 The straight segment 12232 is set parallel to the Z-axis direction. In this way, the straight segment 12232 can avoid the transition between the guide segment 12231 and the second sidewall 1222 through an acute angle, reduce the metal wire generated at the transition between the guide segment 12231 and the second sidewall 1222 during the processing, and improve the processing quality.

[0061] like Figure 6 As shown, the straight segment 12232 is along the thickness direction of the explosion-proof valve 120 (reference). Figure 6 The length of the guide section 12231 (in the Z-axis direction) is B. If the length B is too small, metal wires are easily generated at the transition between the guide section 12231 and the second side wall 1222 during processing, and the metal wires can easily scratch the surface of the explosion-proof valve 120. If the length B is too large, during the welding process between the outer wall of the mounting part 122 and the inner wall of the injection hole 111, the weld mark is not easy to cover the straight section 12232 along the thickness direction of the explosion-proof valve 120, which affects the welding quality and results in a low welding yield.

[0062] Therefore, in this embodiment of the application, the length B of the straight segment 12232 along the thickness direction of the explosion-proof valve 120 is limited to the following range: 0.05mm≤B≤0.2mm. In this way, the problems caused by the aforementioned length B being too large or too small can be effectively improved.

[0063] In one embodiment, the length B of the straight segment 12232 along the thickness direction of the explosion-proof valve 120 can be selected as 0.05mm, 0.15mm, 0.2mm, etc.

[0064] The present application will be further described below with reference to specific embodiments and comparative examples.

[0065] Example 1 The battery may include a casing, electrode assembly, and cover assembly 100. The casing has an opening, and the electrode assembly is disposed within the casing. The cover assembly 100 includes a cover plate 110 and an explosion-proof valve 120. The cover plate 110 is disposed at one end of the electrode assembly and is connected to the casing to close the opening. The cover plate 110 has a liquid injection hole 111, and the explosion-proof valve 120 is disposed within the liquid injection hole 111. The explosion-proof valve 120 includes a bursting part 121 and a mounting part 122. The mounting part 122 is arranged around the bursting part 121, and the inner wall of the mounting part 122 is connected to the bursting part 121. The outer wall of the mounting part 122 is connected to the inner wall of the liquid injection hole 111. The mounting part 122 has a buffer groove 123. The bursting part 121 has a groove 124, and the opening of the groove 124 faces the opposite direction to the opening of the buffer groove 123. The depth of the groove 124 is A, and the thickness of the explosion-proof valve 120 is H.

[0066] In this embodiment, the depth A = 0.3 mm and the thickness H = 1 mm.

[0067] Example 2 This embodiment is basically the same as embodiment 1, except that: Depth A = 0.4 mm, thickness H = 1 mm.

[0068] Example 3 This embodiment is basically the same as embodiment 1, except that: Depth A = 0.5 mm, thickness H = 1 mm.

[0069] Example 4 This embodiment is basically the same as embodiment 1, except that: Depth A = 0.6 mm, thickness H = 1 mm.

[0070] Example 5 This embodiment is basically the same as embodiment 1, except that: Depth A = 0.7 mm, thickness H = 1 mm.

[0071] Example 6 This embodiment is basically the same as embodiment 1, except that: Depth A = 0.8 mm, thickness H = 1 mm.

[0072] Example 7 This embodiment is basically the same as embodiment 1, except that: Depth A = 1mm, thickness H = 2mm.

[0073] Example 8 This embodiment is basically the same as embodiment 1, except that: Depth A = 1.5mm, thickness H = 3mm.

[0074] Example 9 This embodiment is basically the same as embodiment 1, except that: Depth A = 0.35 mm, thickness H = 0.7 mm.

[0075] Comparative Example 1 This comparative example is basically the same as Example 1, except that: Depth A = 0.1 mm, thickness H = 1 mm.

[0076] Comparative Example 2 This comparative example is basically the same as Example 1, except that: Depth A = 0.9 mm, thickness H = 1 mm.

[0077] Test results The explosion-proof valve 120 was tested for damage to the lower plastic layer. Helium oxide testing was used to check the sealing performance and structural strength of the explosion-proof valve 120. The test results are shown in Table 1.

[0078] Table 1 Example 10 The battery may include a casing, electrode assembly, and cover assembly 100. The casing has an opening, and the electrode assembly is disposed inside the casing. The cover assembly 100 includes a cover plate 110 and an explosion-proof valve 120. The cover plate 110 is disposed at one end of the electrode assembly and is connected to the casing to close the opening. The cover plate 110 has a liquid injection hole 111, and the explosion-proof valve 120 is disposed inside the liquid injection hole 111. The explosion-proof valve 120 includes a bursting part 121 and a mounting part 122. The mounting part 122 is disposed around the bursting part 121, and the inner wall of the mounting part 122 is connected to the bursting part 121. The outer wall of the mounting part 122 is connected to the inner wall of the liquid injection hole 111. The mounting part 122 has a buffer groove 123. The mounting section 122 includes a first sidewall 1221, a second sidewall 1222, and a connecting wall 1223. The first sidewall 1221 and the second sidewall 1222 are arranged opposite each other along the thickness direction of the explosion-proof valve 120. The connecting wall 1223 is located between the first sidewall 1221 and the second sidewall 1222. The connecting wall 1223 includes a guide section 12231 and a straight section 12232. The guide section 12231 is connected to the first sidewall 1221, and the straight section 12232 connects the guide section 12231 and the second sidewall 1222. The guide section 12231 extends obliquely from the first sidewall 1221 in a direction away from the axis of the explosion-proof valve 120. The straight section 12232 and the axis of the explosion-proof valve 120 are both arranged parallel to the thickness direction of the explosion-proof valve 120. The length of the straight section 12232 along the thickness direction of the explosion-proof valve 120 is B.

[0079] In this embodiment, the length B = 0.05 mm.

[0080] Example 11 This embodiment is basically the same as embodiment 1, except that: Length B = 0.07 mm.

[0081] Example 12 This embodiment is basically the same as embodiment 1, except that: Length B = 0.09 mm.

[0082] Example 13 This embodiment is basically the same as embodiment 1, except that: Length B = 0.11 mm.

[0083] Example 14 This embodiment is basically the same as embodiment 1, except that: Length B = 0.13 mm.

[0084] Example 15 This embodiment is basically the same as embodiment 1, except that: Length B = 0.15 mm.

[0085] Example 16 This embodiment is basically the same as embodiment 1, except that: Length B = 0.17 mm.

[0086] Example 17 This embodiment is basically the same as embodiment 1, except that: Length B = 0.2 mm.

[0087] Comparative Example 3 This comparative example is basically the same as Example 1, except that: Length B = 0.3 mm.

[0088] Comparative Example 4 This comparative example is basically the same as Example 1, except that: Length B = 0.03 mm.

[0089] Test results The product yield of explosion-proof valve 120 and the welding yield between explosion-proof valve 120 and cover plate 110 were tested. The test results are shown in Table 2.

[0090] Table 2 The basic principles of this application have been described above with reference to specific embodiments. However, it should be noted that the advantages, benefits, and effects mentioned in this application are merely examples and not limitations, and should not be considered as essential features of each embodiment of this application. Furthermore, the specific details disclosed above are for illustrative and facilitative purposes only, and are not limitations. These details do not limit the application to the necessity of employing the aforementioned specific details for implementation.

[0091] The block diagrams of devices, apparatuses, devices, and systems involved in this application are merely illustrative examples and are not intended to require or imply that they must be connected, arranged, or configured in the manner shown in the block diagrams. As those skilled in the art will recognize, these devices, apparatuses, devices, and systems can be connected, arranged, and configured in any manner. Words such as “comprising,” “including,” “having,” etc., are open-ended terms meaning “including but not limited to,” and are used interchangeably with them. The terms “or” and “and” as used herein refer to the terms “and / or,” and are used interchangeably with them unless the context clearly indicates otherwise. The term “such as” as used herein refers to the phrase “such as but not limited to,” and is used interchangeably with it.

[0092] It should also be noted that in the apparatus, equipment, and methods of this application, the components or steps can be disassembled and / or recombined. These disassemblies and / or recombinations should be considered as equivalent solutions of this application.

[0093] The above description of the disclosed aspects is provided to enable any person skilled in the art to make or use this application. Various modifications to these aspects will be readily apparent to those skilled in the art, and the general principles defined herein can be applied to other aspects without departing from the scope of this application. Therefore, this application is not intended to be limited to the aspects shown herein, but rather to be accorded the widest scope consistent with the principles and novel features disclosed herein.

[0094] The above description has been given for purposes of illustration and description. Furthermore, this description is not intended to limit the embodiments of this application to the forms disclosed herein. Although numerous exemplary aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, alterations, additions, and sub-combinations thereof.

Claims

1. A cover plate assembly, characterized in that, include: The cover plate is equipped with an injection hole; An explosion-proof valve is disposed in the injection hole. The explosion-proof valve includes a bursting part and a mounting part. The mounting part is arranged around the bursting part. The inner wall of the mounting part is connected to the bursting part. The outer wall of the mounting part is connected to the inner wall of the injection hole. The mounting part is provided with a buffer groove.

2. The cover plate assembly according to claim 1, characterized in that, The buffer groove has a ring-shaped structure and is arranged around the blasting part.

3. The cover plate assembly according to claim 1, characterized in that, The blasting section is provided with a groove, and the opening of the groove faces the opposite direction to the opening of the buffer groove.

4. The cover plate assembly according to claim 3, characterized in that, The bottom wall of the groove is provided with a scoring groove.

5. The cover plate assembly according to claim 4, characterized in that, The groove includes a first groove segment and a second groove segment distributed circumferentially along the blasting part, wherein the depth of the first groove segment is greater than the depth of the second groove segment.

6. The cover plate assembly according to claim 5, characterized in that, The first slot segment and the second slot segment are connected end to end.

7. The cover plate assembly according to claim 3, characterized in that, The depth of the groove is A, and the thickness of the explosion-proof valve is H. A and H satisfy: 0.3mm≤A≤0.8H.

8. The cover plate assembly according to any one of claims 1 to 7, characterized in that, The mounting unit includes: First sidewall; The second sidewall is disposed opposite to the first sidewall along the thickness direction of the explosion-proof valve; A connecting wall is disposed between the first sidewall and the second sidewall. The connecting wall includes a guide section and a straight section. The guide section is connected to the first sidewall, and the straight section connects the guide section and the second sidewall. The guide section extends obliquely from the first sidewall in a direction away from the axis of the explosion-proof valve, relative to the axis of the explosion-proof valve. The straight section and the axis of the explosion-proof valve are both arranged parallel to the thickness direction of the explosion-proof valve.

9. The cover plate assembly according to claim 8, characterized in that, The length of the straight segment along the thickness direction of the explosion-proof valve is B, and B satisfies: 0.05mm≤B≤0.2mm.

10. A battery cell, characterized in that, include: The casing has an opening; The pole assembly is located within the housing; The cover plate assembly as described in any one of claims 1 to 9, wherein the cover plate is disposed at one end of the electrode assembly, and the cover plate is connected to the housing to close the opening.

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